Mechanism mounting device for circuit breaker



April 13, 1965 J. c. BRUMFIELD 3,178,547

MECHANISM MOUNTING DEVICE FOR CIRCUIT BREAKER Filed May 10. 1961 5 Sheets-Sheet 1 f1-Ell- April 13, 1965 J. c. BRUMFIELD MECHANISM MOUNTING DEVICE FOR CIRCUIT BREAKER Filed May 10. 1961 5 Sheets-Sheet 2 April 13, 1965 J. c. BRuMFn-:LD

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fl Il United States Patent O 3,173,547 MECHANISM MOUNTING DEVICE FR CIRCUIT BREAKER John C. Brumfield, Philadelphia, Pa., assigner to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed May 10, 1961, Ser. No. 109,171 12 Claims. (Cl. 290-168) This invention relates to molded case circuit breakers in general and more particularly to a novel means for mounting the contact operating mechanism to the base.

In the manufacture of molded case circuit breakers it is most desirable from the standpoint of ease and speed of manufacture to mount the contact operating mechanism, and for that matter as many components as possible, by fastening means operable from the front of the base. Typically, the fastening means comprises screws which are received by inserts in the molded base. When it becomes necessary to fasten a member to the front of the base by means operable from the back of the base this is usually a blind operation which is not readily accomplished as front mounting.

In a typical three phase molded case circuit breaker the base is provided With integrally formed partitions which divide the base into three elongated compartments, one for each phase of the circuit breaker. The movable contact arms of all phases are mounted to a common tie rod lso that the contacts of all phases are simultaneously operated into and out of engagement. Because of the tie rod arrangement only a single operating mechanism is required with this mechanism being positioned in the center compartment.

Typically, the contact operating mechanism is assembled to a frame with the assembly taking place externally of the base. Thereafter, the frame having the mechanism components mounted thereon is rigidly secured to the base. The rigid securement is usually accomplished by means of two screws, one at the front and the other at the rear of the frame.

In recent years, designers of molded case circuit breakers have been striving to improve interrupting ability while reducing the size of thev circuit breaker housings. In so doing, the contacts, conductors, and contact operating mechanism occupy an increasing proportion of the available space Within the molded housing. Because of this, it has been found most dit'licult to gain access from the front of the base to the screws which normally secure the mechanism frame to the base.

Rather than resorting to the utilization of fastening means operable from behind the base, this invention provides novel means whereby hook means and a single screw operable from in front of the base are utilized to rigidly secure the contact operating mechanism frame to the base at the front side thereof.

This is accomplished by means of an insert molded into the base or by bracket means secured to the base prior to mounting of the contact operating mechanism. The frame is provided with hook formations at one end thereof which engage the insert or brackets to position one end of the circuit breaker operating mechanism. The other end of the circuit breaker operating mechanism is secured in place by a single screw means which is received by an insert molded in the base. Thus, the cornplete mounting of the circuit breaker contact operating mechanism takes place by means operable from the front of the base.

Accordingly, a primary object of this invention is to provide a circuit breaker construction including novel means for securing the contact operating mechanism in its operative position.

ICC

Another object is to provide a molded case circuit breaker having hook engaging means on the front side thereof which cooperate with means carried by the frame of the contact operating mechanism so that a single screw means may be utilized to secure the contact operating mechanism in place.

Still another object is to provide a molded case circuit breaker in which one end of the contact operating mechanism isV secured in place by hook means and the other end is secured in place by a single screw means operable from the side of the circuit breaker base to which the operating mechanism is mounted.

These as well as other objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE 1 is a perspective of a circuit breaker constructed in accordance with the teachings of the instant invention with the cover of the circuit breaker being removed to reveal theV internal mechanism thereof.

FIGURE 2 is a longitudinal cross section of the circuit breaker of FIGURE l taken through line 22 of FIG- URE 1 looking in the directionV of arrows 2 2.

FIGURE 3 is a plan view of the housing base with the operating elements of the circuit breaker dismounted.

FIGURES 4 and 5 are cross sections of the base taken through lines 4-4 and 5 5, respectively of FIGURE 3 looking in the directions of the respective arrows.

FIGURE 6 is a plan view of one of the brackets forming the hook means for securing the contact operating mechanism.

FIGURES 6a and 6b are side and end views, respectively of the bracket of FIGURE 6 looking in the direction of FIGURE 7 is a perspective illustrating the contact operating mechanism frame and the manner in which the hook thereof cooperates with the mounting bracket.

' FIGURE 8 is a side elevation illustrating the securemeut of the mechanism mounting bracket to the base.

FIGURE 9 is a plan View of the contact operating mechanism mounted to the base.

Now referring to the iigures, circuit breaker 10 cornprises a molded housing having base 11 and removable cover 12. Base 11 is provided with longitudinal partitions 14, 15 which divide base 11 into three elongated compartments, one for each phase of circuit breaker lil. Similar longitudinal partitions (not shown) are provided for cover 12.

The current path through each phase of circuit breaker 10 comprises load terminal connector 16, load terminal strap, including loop portion 18 having portion 20 of reduced cross sections which serves as a heater for bimetal trip element 21 connecting member 22, ileXible member 23 to one endV of movable Contact arm 24. Movable contact 25 is mounted to the other end of contact arm 24 and is engageable with stationary contact 26 mounted to one end of line terminal strap 27 which is connected by screw means 29 to tulip connector 28 forming the line terminal connection.

Trip free operating mechanism 30 is provided to pivot movable tie bar 99 about an axial pivot (not shown). All three contact arms 24 are carried by tie bar 99 for simultaneously operating movable contacts 25 of all three phases into and out of engagement with their associated stationary contacts 26. Operating mechanism Sil is'an overcenter toggle type well known to the art and is fully described in copending application, Serial No. 108,812, tiled May 9, 1961, entitled U-Shaped Cradle for Circuit Breaker, invented by Ernest R. Wortmann, and assigned to the assignee of the instant invention. Handle 9S is provided for manualoperation of mechanism 39 while overload device 97 is provided for automatic tripping of: mechanism 3d.

Arc extinguishing means in the form of arc chute 40 is operatively positioned by suitable formations in base 11 to receive electric current arcs drawn between cooperating contacts 25, 26 upon separation thereof. Since the theory of arc interruption is well understood to those skilled in the art elaboration of this point will not be undertaken at this time.

Briefly, operating mechanism 30 comprises generally U-shaped frame 31 to which the o ther elements of the mechanism 30 are mounted. That is, pins 32 extend outwardly from frame 31 and form pivotal supports for the lower end of inverted U-shaped operating member 33 to which handle 98 is mounted. Operating springs 34 are mounted at the upper ends thereof to the web of operating member 33 and the lower ends of spring 34 are mounted to triangular member 35 which is pivotally mounted to the knee pin 37 joining toggle linkages 38, 39. The upper end of upper linkage 38 is pivotally mounted at 41 to cradle 31 latchable by overload means 97, while the lower end of lower linkage 39 is mounted at 42 to inverted U-shaped member 43 which carries the movable contactiarm 24 of the center phase. Member 43 is carried by tie bar 99 which extends transversely into all three compartments and also carries two other members 43 which in turn carry the contact arms 24 of two outer phases.

Each of the arms of the U-shaped member comprising frame 31 includes at the front of frame 31 a hooklike formation 45 which, as clearly seen in FIGURE 7, engages the hook formation 46 of bracket 47. Screw means 48, operable from the back of base 11, extends through base aperture 51 as is clearly seen in FIGURES 3 and 4. Two brackets 47 are mounted within the central compartment of base 11 with the open ends of their hook notches 53 facing each other.

During the manufacturing process for circuit breaker 10, screw means 43 is received by the threads of bracket aperture 49 to secure bracket 47 to the front of base 11. Contact operating mechanism 30 is assembled externally of base 11. Thereafter, hook formations 45 of frame 31 are mounted in cooperating relationship with the hook notches 53 of brackets 47 to secure the front end of frame 31 in position. Screw 61, which passes through aligned apertures in conducting member 22 and load terminal strap 17, passes through frame aperture 62 and engages the threads of insert 63 molded in base 11.

It is readily seen that screw 61 secures the back end of `frame 31 in place with screw 61 being operable from the front of base 11. The arms of frame 31 are so constructed that as screw 61 is tightened interference takes place at 65 between frame 31 and brackets 47. This is an intentional interference which tensions hook means 45, 46 to hold frame 31 in a fixed position relative to base 11.

Thus, this invention provides novel means whereby construction of a molded case circuit breaker is readily accomplished even when the contacts, conductors, and contacting operating mechanism occupies a substantial portion of the case volume. This means comprises a hook formation on the front surface of the base which is engaged by a cooperating hook formation carried by the operating mechanism frame at one end thereof. The other end of the frame is secured by a screw means which upon tightening drives the frame against interfering means carried by the base to tension the hook means connection for rigid securement of the frame to the base.

Although I have here described preferred embodiments of my novel invention, many variations and modifications will now be apparent to those skilled in the art, and I therefore prefer to be limited not by the specific disclosure herein but only by the appending claims.

I claim:

1. A circuit breaker comprising a housing, a pair of cooperating contacts disposed within said housing, a mechanism disposed within said housing for operating said contacts into and out of engagement; said mechanism including a frame to be securably mounted at an internal region of said housing; other elements of said mechanism mounted to said frame; said frame having a first and second end; hook means securing said first end of said frame to said housing and screw means securing said second end of said frame to said housing; said other elements disposed in a region of said frame overlying the end region of said frame including said hook means, whereby said hook means is inaccessible after said frame is located at said internal region of said housing; said hook means and screw means preventing movement of their respective frame ends away from said housing.

2. A circuit breaker comprising a housing, a pair of cooperating contacts disposed within said housing, a mechanism disposed within said housing for operating said contacts into and out of engagement; said mechanism including a frame to be securably mounted at an internal region of said housing; other elements of said mechanism mounted to said frame; said frame having a first and second end; hook means securing said first end of said frame to said housing and screw means securing said second end of said frame to said housing; said other elements disposed in a region of said frame overlying the end region of said frame including said hook means, whereby said hook means is inaccessible after said frame is located at said internal region of said housing; said housing including a base; said mechanism being mounted on a first side of said base; means providing access of said screw means from said first side after said frame is mounted to said base; said hook means and screw means preventing movement of their respective frame ends away from said first side.

3. A circuit breaker comprising a housing, a pair of cooperating contacts disposed within said housing, a mechanism disposed within said housing for operating said contacts into and out of engagement; said mechanism including a frame to be securably mounted at an internal region of said housing; other elements of said mechanism mounted to said frame; said frame having a first and second end hook means securing said first end of said frame to said housing and screw means securing said second end of said frame to said housing; said other elements disposed in a region of said frame overlying the end region of said frame including said hook means, whereby said hook means is inaccessible after said frame is located at said internal region of said housing; said housing including a base; said mechanism being mounted on a first side of said base; means providing access of said screw means from said first side after said frame is mounted to said base; said hook means and screw means preventing movement of their respective frame ends away from said first side; said base being comprised of molded insulating material; said hook means including metal bracket means carried by said base on said first side; said frame comprising a metal member having a formation in operative engagement with said bracket means.

4. A circuit breaker comprising a housing, a pair of cooperating contacts disposed within said housing, a mechanism disposed within said housing for operating said contacts into and out of engagement; said mechanism including a frame, other elements of said mechanism mounted to said frame; said frame having a first and second end; hook means securing said first end of said frame to said housing and screw means securing said second end of said frame to said housing; said other elements disposed in a region of said frame overlying the end region of said frame including said hook means, whereby said hook means is inaccessible after said frame is mounted to said housing; said housing including a base; said mechanism being mounted on a first side of said base; means providing access of said screw means from said first side after said frame is mounted to said base; said base being comprised of molded insulating material; said hook means including metal bracket means carried by said base on said first side; said frame comprising a met-al member having a formation in operative engagement with said bracket means; interference means on the base first side against which said frame is driven through tightening of said screw means whereby said hook means is tensioned.

5. A multiphase circuit breaker comprising a housing including a base having means dividing said base into an elongated compartment for each of the phases, a pair of cooperating contacts for each of the phases disposed within an individual one of said compartments, a single operating mechanism for simultaneously operating the cooperating contacts of all phases into and out of engagement; said operating mechanism being disposed within a single one of said compartments and including a frame to be securably mounted at an internal region of said housing; other elements of the mechanism secured to said frame; said frame having a first and second end; a first and a second means at the first and second ends, respectively, of said frame cooperating to removably mount said frame in a fixed position on a first side of said base; said first and second means preventing movement of said first and second ends, respectively, away from said first side; said other elements disposed in a region of said frame overlying said first end, whereby said first means is inaccessible from said first side; means providing access of said second means from said first side after mounting of said frame to said base.

6. The circuit breaker of claim 5 in which the rst means comprises a hook device and the second means comprises a screw device.

7. The circuit breaker of claim 6 in which the frame comprises a generally U-shaped member whose web is forced against a formation of said base upon tightening of said screw device whereby said hook device is tensioned.

8. A multiphase circuit breaker comprising a housing including a base having means dividing said base into an elongated compartment for each of the phases, a pair of cooperating contacts for each of the phases disposed Within an individual one of said compartments, a single operating mechanism for simultaneously operating the cooperating contacts of all phases into and out of engagement; said operating mechanism being disposed within a single one of said compartments and including a frame to be securably mounted at an internal region of said housing; other elements of the mechanism secured to said frame; said frame having a first and second end; a first and a second means at the first and second ends, respectively, of said frame cooperating to removably mount said frame in a fixed position on a first side of said base; said first and second means preventing movement of said first and second ends, respectively, away from said first side; said other elements disposed in a region of said frame overlying said first end, whereby said first means is inaccessible from said first side; means providing access of said second means from said first side after mounting lof said frame to said base; said first means comprising ybrackets mounted on said first side and having inwardly extending projections spaced from said first side; said frame including spaced sidewalls each having la hook formation, comprising, said first means, wherein said projections are disposed; said second means comprising a screw device whose threads engage threaded formations carried by the base.

9. The circuit breaker of claim 8 which includes means accessible from a second side of the base for mounting of the brackets.

10. The circuit breaker of claim 8 in which the hook formations are open at the portions thereof nearest the second end of said frame.

11. A circuit breaker comprising in combination: a pair of cooperating contacts movable between an engaged and disengaged position; a contact .operating sub-assembly including a plurality of operating parts mounted to a frame; a housing, having a base; first and second connecting means for removably mounting first and second ends of said frame to the base of the housing from an internal surface thereof; said operating parts disposed in a region of said frame overlying said first end of said frame, including said first connecting means, whereby said first connecting means is inaccessible after -said frame is 1ocated at said internal surface of said base; said first connecting means including cooperating surfaces secured t0 said frame and said internal surface of said base to provide means engageable upon positioning said frame at said internal surface for preventing movement of said frame away from said base.

12. The circuit breaker of claim 11, wherein said first means comprises a hook device; said second means comprises a screw device; said frame comprises a generally U-shaped member having a web; means forcing said web against a formation of said base upon tightening of said screw device whereby said hook device is tensioned.

References Cited by the Examiner UNITED STATES PATENTS 992,009 5/11 Lang ZOO-168 2,065,356 12/36 Von Hoorn 200-168 2,917,267 12/59 Riddle 248-361 BERNARD A. GILHEANY, Primary Examiner.

MAX L. LEVY, Examiner. 

11. A CIRCUIT BREAKER COMPRISING IN COMBINATION: A PAIR OF COOPERATING CONTACTS MOVABLE BETWEEN AN ENGAGED AND DISENGAGED POSITION; A CONTACT OPERATING SUB-ASSEMBLY INCLUDING A PLURALITY OF OPERATING PARTS MOUNTED TO A FRAME; A HOUSING, HAVING A BASE, FIRST AND SECOND CONNECTING MEANS FOR REMOVABLY MOUNTING FIRST AND SECOND ENDS OF SAID FRAME TO THE BASE OF THE HOUSING FROM AN INTERNAL SURFACE THEREOF; SAID OPERATING PARTS DISPOSED IN A REGION OF SAID FRAME OVERLYING SAID FIRST END OF SAID FRAME, INCLUDING SAID FIRST CONDUCTING MEANS, WHEREBY SAID FIRST CONNECTING MEANS IS INACCESSIBLE AFTER SAID FRAME IS LOCATED AT SAID INTERNAL SURFACE OF SAID BASE; SAID FIRST CONNECTING MEANS INCLUDING COOPERATING SURFACES SECURED TO SAID FRAME AND SAID INTERNAL SURFACE OF SAID BASE TO PROVIDE MEANS ENGAGEABLE UPON POSITIONING SAID FRAME AT SAID INTERNAL SURFACE FOR PREVENTING MOVEMENT OF SAID FRAME AWAY FROM SAID BASE. 